Chemicals in plastics and cosmetics tied to early births

NEW YORK (Reuters Health) - Chemicals called phthalates,
found in plastics and cosmetics, may be linked to a raised risk
of babies being born early, suggests a new study.

Researchers found that women who delivered babies before 37
weeks gestation had higher levels of phthalates in their urine,
compared to women who delivered their children at full term,
which is 39 weeks.

"Preterm birth is a real public health problem," said John
Meeker, who led the study. "We're not really sure how to go
about preventing it, but this may shed light on environmental
factors that people may want to be educated in."

Meeker, from the University of Michigan School of Public
Health in Ann Arbor, added, "We knew that exposure to phthalates
was virtually ubiquitous here in the U.S. and possibly worldwide
and preterm births increased for unknown reasons over the past
several decades."

Phthalates are included in products for a variety of
reasons, include to make plastic flexible.

Past studies also have found evidence that would suggest the
chemicals may be tied to earlier births.

"There are many possible routes of exposure depending on the
chemical of interest and the scenario," Meeker said. Most
commonly, the chemical enters the body through food and
beverages. It may also be absorbed through the skin.

For the new study, the researchers used data from a study
conducted at Brigham and Women's Hospital in Boston between 2006
and 2008.

During the study, pregnant women were asked to fill out
surveys and provide urine samples throughout their pregnancies.
The researchers compared 130 mothers who delivered their babies
before 37 weeks to 352 women who delivered their babies at term.

While each woman provided numerous urine samples during
their pregnancies, the researchers analyzed three to measure the
amount of phthalates in their bodies.

They looked for breakdown products of a phthalate chemical
known as DEHP.

Overall, the two byproducts MEHP and MECPP were more
abundant in women who delivered their children early, compared
to women who delivered after 37 weeks. That was also true for
MBP, a byproduct of Dibutyk phthalate.

According to the U.S. Environmental Protection Agency, those
chemicals are used to make products - such as plastic pipes,
shower curtains and food packaging - soft and flexible.

Each of the phthalates examined was linked to a risk
increase of anywhere from 16 percent to 65 percent increase in
risk for preterm birth.

About one of every eight infants is born prematurely in the
U.S., according to the Centers for Disease Control and
Prevention.

Shanna Swan, who wrote an editorial accompanying the new
study in JAMA Pediatrics, said that difference may not mean much
to an individual woman, but it adds up across a large
population.

Swan is a professor Department of Preventive Medicine at the
Icahn School of Medicine at Mount Sinai in New York.

"There are a lot of indications or warnings that signal that
women avoid phthalates when they can," she said. "I say 'when
they can' because it's difficult."

"Most of the exposures are silent and we are not aware of
them," she added. "We don't know how to avoid them."

Previous studies have suggested that people who use fresh
and organic produce - such as certain religious groups - have
lower phthalate levels," Swan said.

She added, however, that not many studies have examined the
relationship between phthalates and preterm births.

Some studies, according to the researchers, have found no
negative side effects from phthalate levels, but those only used
levels from one urine sample. Phthalate levels can change during
pregnancy.

Meeker said the new study can't prove higher phthalate
levels caused women to deliver early or if they should stay away
from the chemicals.

"Our study wasn't really geared to look at that," he said.
"Women may want to limit exposure if they can, but there are so
many different points of exposure which makes it difficult."